1. Introduction & Outline Particulate Measurement 1) PM10 – Particulate Matter < 10 microns 2) PM2.5 – Particulate Matter < 2.5 microns - Measured with different instruments. Cache Valley Meteorological Issues 1)Strong winter inversions. 2)Cold. Cache Valley Particulate Issues 1)Organic Carbon (OC) - Wood Burning 2)Nitrate (NO3) – Mobile Sources/Power Plants 3)Ammonium (NH4) - Agriculture

2. Clear skies promote surface cooling and cold air drainage from mountain slopes. The cold dense air collects and pools in valley bottoms such as the Cache Valley.

3. Temperature 0 10 30 50 F Fog/Clouds Wind Speed Wind Direction Down Valley “Warm” Elevation “Cold” Profile of a typical Cache Valley inversion. Coldest air is trapped less then 100 meters above ground. “Strength” of an inversion depends on the Depth of the inversion and the change in temperature within the inversion.

4. Chemistry & Meteorological Data Sampling Dates: 12/24/01 12/27/01 12/30/01 01/02/02 02/02/02 02/04/02 02/07/02

5. Meteorological Summary Winter inversion development. 8-25 degrees F colder at Logan. Lighter winds at Logan.

6. PM10 OCECNO3NH4 Cottonwood6983206 Hawthorne7173206 N. Salt Lake7172196 Ogden7010*3214 Logan83 *10 *233 *12 * % of PM10OCECNO3NH4 Cottonwood124299 Hawthorne114288 N. Salt Lk.103278 Ogden14*4305 Logan12340 *15 * Logan Avg.1234015 Others Avg.124298 Table Summary: Logan: Highest Average [PM10] Logan: Highest Average [OC] Logan: Highest Average [NO3] Logan: Highest Average [NH4] NO3 concentrations & percentage of PM10 are far greater at Logan compared to the other monitors. Units:  g/m 3

8. PM2.5 NO3NH4 Bountiful 521910 Cottonwood 592211 N. Salt Lake 582412 Ogden 542312 Washington Terrace 492110 Logan 76 *35 *18 * % of PM2.5PM10NO3NH4 Bountiful NA3619 Cottonwood 853719 N. Salt Lake 814221 Ogden 784222 Washington Terrace NA4220 Logan 9246 *23 * Logan Avg. 4623 Others Avg. 4020 Table Summary -Logan: Highest Average [PM2.5]. -Logan: Highest Average [NO3]. -Logan: Highest Average [NH4]. More PM10 at Logan is PM2.5. Why? Secondary Formation. Units:  g/m 3

9. Figure Summary PM2.5, NO3, NH4 greater in the Cache Valley Units:  g/m 3

10. PM10 and PM2.5 Data Table Summary Most of Logan PM is PM2.5 Salt Lake Valley PM contains more primary PM (PM10) More NO3 & NH4 at Logan

11. Units:  g/m 3, Fahrenheit

12. Meteorology – Chemistry Summary Inverse Relationship Between: 1) RH & NO3 2) RH & NH4 Why? Rapid particle growth (>10 microns) Inverse Relationship Between: 1) Temperature & NO3 2) Temperature & NH4 Why? Particle formation physics at cold temperatures.

13. -Sample Size = 7 -Surplus NH4 (1.6:1.0) -Sample Size = 128 -Surplus NH4 (1.6:1.0) Figure Summary - Cache and Salt Lake Valleys are NOT NH4 limited (excess NH4). - Cache Valley NH4 = Salt Lake Valley NH4 PM2.5 NH4 : NO3

14. Figure Summary - Organic Carbon dominates in both valleys. - More Organic Carbon in Cache Valley then in Salt Lake Valley. - Equal Elemental Carbon in both valleys. PM10 OC : EC -Sample Size = 7 -Lots of OC (0.18:1.0) -Sample Size = 128 -Lots of OC (0.24:1.0)

15. 4 Conclusions (1) … Cache Valley PM occurs almost entirely in the PM2.5 size fraction. More primary PM in the Salt Lake Valley. OC, NO3, NH4 are higher in the Cache Valley compared to the SLV. PM2.5 NO3NH4 Bountiful 521910 Cottonwood 592211 N. Salt Lake 582412 Ogden 542312 Washington Terrace 492110 Logan 76 *35 *18 * % of PM2.5PM10NO3NH4 Bountiful NA3619 Cottonwood 853719 N. Salt Lake 814221 Ogden 784222 Washington Terrace NA4220 Logan 9246 *23 * Logan Avg. 4623 Others Avg. 4019

16. Conclusions (2 & 3) … “Extreme” cold contributes to: Ammonium nitrate particulate formation. Wood smoke contribution in the Cache Valley is likely significant.

17. Conclusions (4) Cache Valley has excess Ammonia. - NH4:NO3 = 1.6:1.0 Target NOx not NH3

18. Considerations : 1) Logan monitor location. 2) More speciated data.